The Happiness Project written by Gretchen Rubin

http://www.happiness-project.com
I just finished reading this brilliant book right now. I found out about it when I looked at Chapter´s top 10 list. Chapter´s is huge Bookstore chain in Canada where you also can order books online. I found alot of really good books there.
Anyway, this book is very informative, has alot of good tips you can use in your daily life and Gretchens has done alot of reseach for it. I got tons of information out of it and lots of good tips for other books.
It definitely made it in my personal top 10 list!
Elisabeth - it´s worth buying it and to do read Gretchens blog and to sign up for her newsletter ;).